1. Field of the Invention
The present invention relates to a fuel package that stores liquid fuel, a power generation device that comprises the fuel package and a power generation module that generates electric energy by the chemical reaction of the liquid fuel supplied from the fuel package, and a remaining fuel amount measuring device which measures the remaining amount of liquid fuel left in a vessel which stores liquid fuel stored and supplies the fuel to the power generation module.
2. Description of the Related Art
In recent years, compact electronics device, such as a portable telephone, a laptop computer, a digital camera, a wrist watch, a PDA (Personal Digital Assistance), and an electronic organizer, etc., are remarkably progressing and developing.
As the power source for the above compact electronics device, primary battery such as an alkaline battery and a manganese dry battery, and/or secondary battery such as a nickel cadmium battery, a nickel hydrogen battery, or a lithium-ion battery, are used. However, looking from the aspect of the usage efficiency of energy, energy is not always used efficiently in primary batteries and secondary batteries. On the other hand, fuel cells directly derives electric energy from chemical energy by electrochemically reacting fuel in the cell and the oxygen in the atmosphere, and are positioned as batteries that have good prospects for the future.
Therefore, in recent years, to replace the primary batteries and secondary batteries, research and development of the fuel cells with high usage efficiency of energy, is being carried out.
Because the compact electronics device such as above, are small, they are used in various directions and positions, in accordance with the scene used by the user. For example, a laptop computer is carried around, being held under one's arm, a portable telephone is carried around in a state where it is stored without much care in a pocket or a bag, and in some cases, people talk on the portable telephone, tilting the body of the portable telephone. Because the portable telephone constantly receives electric waves, it consumes electric power even at a stand-by-state. Therefore, in a case where a fuel cell is applied as a power source for these kind of electronic devices, it is preferable that fuel is stably supplied to the fuel cell even when the fuel cell or the fuel vessel that supplies fuel to the fuel cell is tilted as well as it is not tilted.
The fuel cell disclosed in Unexamined Japanese Patent Application KOKAI Publication No. 2001-93551, comprises a fuel cell main body wherein a proton transmitting plate is interleaved between a fuel electrode and an oxygen electrode, and a fuel vessel that stores liquid fuel, and is connected to the fuel cell main body. Pores are formed at the fuel vessel. Penetrating material is placed in the fuel vessel. The penetrating material extends from the fuel vessel to a connecting unit of the fuel cell main body. The liquid fuel in the fuel vessel penetrates to the connecting unit through the penetrating material, the liquid fuel that penetrated to the connecting unit is supplied to the fuel cell main body by capillary force, and electric energy is derived in the fuel cell main body. Even if the liquid fuel is consumed, because pores are formed at the vessel, the pressure balance between the fuel vessel and outside is maintained. If the fuel vessel becomes empty, it can be changed to a new one.
In a case where the fuel cell disclosed in Unexamined Japanese Patent Application KOKAI Publication No. 2001-93551 is placed in the portable compact electronics device, because the electronics device is used in various positions and directions (inclination), the fuel vessel also becomes various positions and directions (inclination). Therefore, according to the position/direction (inclination) of the fuel vessel, or the remaining amount of the liquid fuel, there are cases where the liquid fuel does not contact the penetrating member, and there is a possibility that even if the fuel vessel is not empty, supply of the liquid fuel to the fuel cell stops. Because the liquid fuel that penetrates to the penetrating material is retained in the penetrating material, by capillary force, there is a case where in the process of the liquid fuel being consumed, at the time that the capillary force that operates to the penetrating material, and the capillary force that operates at the side of the fuel cell main body match, liquid fuel is not supplied from the penetrating material to the fuel cell main body. Therefore, there is a fear that liquid fuel is left in the liquid fuel vessel.
Further, because the liquid fuel is supplied to the fuel cell main body by capillary force, there are cases where it takes a long time from the time that the fuel vessel is connected to the fuel cell main body, till the time the liquid fuel reaches the fuel cell main body.
Also, because the electronics device and the fuel vessel is used in various positions and directions, the liquid fuel in the fuel vessel flows to various position in accordance with the position of the fuel vessel. Therefore, it is difficult to quantitatively measure the remaining amount of fuel in the fuel vessel.